Counting and timing circuits



E. D. BURLINGAME ET AL COUNTING AND TIMING CIRCUITS Oct. 4, 1949 Filed Aug. 25, 1944 Patented Oct. 4, 1349 COUNTING AND TIMING CIRCUITS Ernest D. Burlingame, Eggertsville, and Madison G. Nicholson, Jr., Snyder, N. Y., assignors to Colonial Radio Corporation, Buffalo; N. Y.

Application August 23, 1944, Serial No. 550,828 8 Claims. (01. 175-320) This invention relates to certain new and usetrons, which are successively ionized or fired by incoming impulses.

To provide such a counting circuit in Whlch as each tube successively ionizes or fires, it extin- I guishes the preceding tube.

To provide circuits of the class described in which there is no theoretical limit to the number of tubes which may be employed for successive operation.

To provide counting apparatus of the class described which is free from the possibility of erroneous or incorrect counting and which, therefore, may-be utilized in apparatus where faulty operation cannot be tolerated.

Still other objects and advantages of our invention will be apparent from the specification.

The features of novelty which we believe to be characteristic of our invention are set forth with particularity in the appended claims. Our invention itself, however, both as to its fundamental principles and'as to its particular embodiments,

will best be understood by reference to the specification and accompanying drawing, in which the single figure is a circuit diagram of one form of circuit in accordance with our invention.

Referring now more particularly to the drawing, we have shown a circuit particularly ar ranged to count by fours, but it will be understood that a smaller number of tubes may be provided if-the maximum number of impulses desired to be counted is less than four. Also, more particularly, the system can be extended by adding additional stages without theoretical limitif it is desired to count more than fours.

Incoming pulses may be received upon th input ing resistance RIB and through the energizing winding of relay Rel to back contact A2'b of relay 2, thence through armature A2 of relay 2 to back contact A3'b, of relay 3, thence through blade A3 of relay 3 to back contact A4b of relay 4, and through blade A4 of relay 4 to +3.

Cathode lc may be connected through resistance R-l2 to the +3 supplyand through resistance Rl3 to ground, and the control electrode lg may be connected to cathode lc. Cathode lc may be connected through condenser Cl3 to control electrode 2g of tube T2. A connection may also be provided from cathode lc through condenser Cl2 to ground and through resistances RM and Eli to ground.

Tube T2 may be a thyratron having cathode 20, a pair of control electrodes 2g and 2sg, and anode 2a. The cathode may be connected through resistance R22 to +B, control'electrode 29 through resistance Rl5 to ground, and second control electrode 2sg through condenser C2l to the high potential input terminal and through resistance R2l to ground.

Anode 2a may be connected through resistance R26, the energizing winding of relay 2 to back contact A3'b and thence to +3 as in the case of anode la, and cathode 20 may likewise be connected through condenser C22 to ground and through resistances R24 and R25 in series to ground and through capacity C23 to control electrode 3g of tube T3.

Tube T3 may be a thyratron having cathode 3c, control electrodes 39 and 3sg, and anode 3a. Cathode 3c may be connected through resistor R32 to +B, through resistances R33 condenser C32 in parallel to ground, through resistances R34 and R35 in series to ground, and through condenser C33 to control electrode 49 of tube T4. Anode 3a may be connected through resistance R36 and energizing winding of relay Re3 to back contact AM of relay Hell and to +3 as before.

Tube T4 may likewise be a thyratron having cathode 40, control electrodes 40 and. 4sg, and anode 4a.- through resistance R42 to +3 and through resistance R43 to ground. Control electrode 4g may be connected through resistance R35 to ground and control electrode 4sg may be connected through condenser GM to the high potential input terminal and through resistance RM to ground. Anode 4a may be connected through resistance R46 and actuating winding of relay 4 to the +3 side of the winding of relay 3 and thus to +B in the same manner as relay 3.

Relay I may comprise armature Al normally The cathode may be connectedcontact Alf may be connected to output terminal TI.

Relay Re2 controls armature A2 and A2, and these armatures are biased against back contacts A2b and A2b respectively and closed against front contacts A2! and A2! by the energizing of relay Re2. Closure of relay Re2 connects the armature A2 to output terminal T2.

Relay R83 may have armatures A3 and A3. and these are normally biased against back contacts A31) and A3'o, and are moved to front contacts A3! and A3! by the closure of relay Rel. Closure of relay Re3 connects armature A3 to output terminal T3 and armature AI may be connected to back contact A2b, armature A2 to back contact MD, and armature A3 to the source of +A voltage.

In the present instance, only three output terminals, Tl, T2, and T3, are shown, since in the present instance it is desired to provide only three controls; tube T4, which operates in response to the fourth received impulse, not controlling any external apparatus. It will be understood, however, that should this be desired, an output terminal T may be provided, connected to contact A'b, to be energized by the operation of relay 4.

The operation of the circuit may now be understood by reference to the following description: Tubes TI, T2, T3, and T4 are preferably of the gas-filled variety, such as type 2050, and having characteristics such that if either or both control grids are maintained at a sufficient negative potential with respect to cathode, ionization of the tube cannot occur. However, if the voltages of both control electrodes are not suiliciently negative. ionization will occur and plate current will flow wit out grid control until the plate circuit is interrupted.

A l cathodes. Ic, 2c, 30. and 4c, are maintained at the same positive potential (in the absence of ionization in anv tube) by voltage dividers consisting of resistances RI2 and Rl3 for cathode Ic. resistances R22 and R23 for cathode 20, re-' Sistances R32 and R33 for cathode 3c, and resistances R42 and R43 for cathode 40. When any tuhe ionizes, the flow of plate current causes the potential of the cathode to rise in a positive direction. The. volta e dividers RH and I5, R24 and 25. and R34 and 35. are so arranged that the volta e at the midpoint when a tube (except the las is ionized is the same as the voltage at the cat ode of the following tube when the said followin tube is not ionized.

T us t e volta e difference between any of the control e ectrodes 20. 3a. and 8a and the respective cathode 20, 3c. and 4c is either zero or some ne ative value. de ending on whether the previous tube is ioni ed. The voltage difference between the control electrode Ig and its cathode I0 is alwa s zero. since. as will be observed, these two are directly connected.

The second control electrode, Isg. 2sg, 3sg, and 4s u. of each tube is connected to the source of positive vo ta e pulse through the respective condensers CI I, C2 I. G3 I, and CH, and each is maintained at a normal potential more negative than its respective cathode, but returning to +3 throu h resistance RII, R2I. R3I. and R4! respectivelv to ground. to which -B is connected. The amplitude of the input voltage pulses may be at least sufflcient to momentarily raise the second control electrode. Isa. 2s.a. 38g. and lsg. to a potential equal to the normal cathode potential.

when a pulse is applied to the input terminals TI, all of the second control electrodes are momentarily raised to the potential of their respective cathodes. First grids 2g, 3g, and 4a are at a negative potential with respect to their respective cathodes, and so tubes T2, T3, and T4 are prevented from ionizing on the first impulse.

The first tube Tl has no first grid bias and, therefore, ionizes. and the plate current energizes relay I, closing armature AI against front contact All and thereby applying potential to terminal TI, which may be used to control a circuit which it is desired to have respond to the first impulse.

When the first tube ionizes, the voltage between the grid 2g and the cathode of the second tube T2 isv reduced to zero, the next impulse raises all second control electrodes, Isa, 2sg, 33g, and 48a, to cathode potential, and tube T2 then ionizes. Tubes T3 and T4, however, will not ionize on the second impulse because their grids 3g and 40 still have a negative bias suflicient to prevent ionization.

The flow of plate current in tube 2 energizes relay Re2 and connects armature A2 against front contact A2), thereby applying voltage to terminal T2. Simultaneously the plate current of tube TI is interrupted by opening of the plate circuit at back contact A2b, but relay Re2 and tube Tl. therefore, deionizes, deenergizing relay Rel and interrupting the circuit to terminal TI at front contact Alf of relay Rel.

The operation proceeds similarlyfor the third impulse, which causes tube T3 to ionize and thereby prepares tube T4 to be ionized on the fourth impulse. The fiow of plate current in tube T3 energizes relay Re3 to close armature A3 against front contact A3f, connecting T3 to A+ and also interrupting the flow of plate current through relay 2 at back contact A3'b, thereby deionizing tube T2 and causing opening of the control circuit from terminal T2 at front contact A2f.

Reception of the fourth impulse causes ionization of tube T4, thereby energizing relay Re4 and closing armature A4 against front contact A4! and interrupting the plate circuit of all of the tubes at back contact AM). This causes deionization of tubes T3 and T4 and restores the apparatus to initial position ready to respond to the first impulse of a second counting cycle.

When any tube in the series is caused to ionize, the current in the cathode resistordoes not reach its full value instantaneously, but rises exponentially at a rate determined by the relay inductance and plate circuit resistance and, therefore, a length of time T elapses between the time when ionization begins in any tube and the time when the next successive tube is capable of being ionized by the next impulse, and this limits the rapidity with which impulses may be counted. For thi reason condensers CI3, C23, and C33 are provided in parallel with resistances RI4, R24, and R34, respectively.

Provision of these capacities gives a leading phase characteristic to the circuits and partly compensates for the inductive lag and permits the voltage of the following grid to rise to its final value considerably more rapidly than it would were these condensers not provided, and, therefore, permits the apparatus to count impulses separated by periods of time considerably less than would otherwise be possible.

For the purpose of completing this disclosure, but not in limitation, the following table of values is given:

Resistance Ohms Resistance Ohms While we have shown and described certain preferred embodiments of our invention, it will be understood that modifications and changes may be made without departing from the spiritand scope thereof, as will be clear to those skilled in the art.

In this application we have explained the principles of our invention and the best mode v in which we have contemplated applying those principles, so as to distinguish our invention from other inventions; and we have particularly pointed out and distinctly claimed the part, improvement, or combination which we claim as our invention or discovery.

We claim:

1. In a counting circuit, in combination, a plurality of'thyratrons, each having a cathode, an anode, and a pair of control electrodes, a relay in'the space current circuit of each'of said thyratrons, contacts actuated by said relays to set up successive .circuits upon ionization of each tube, and means for applying a voltage drop in the space current circuit of each of said thyratrons to one control electrode of the successive tube to prepare each successive tube for operation, and meansfor applying impulses to be counted to the other control electrodes of all said thyratrons.

2. In a counting circuit, in combination, a plurality of thyratrons, each having a cathode, an

anode, and a pair of control electrodes, a relay in the space current circuit of each of said thyratrons, contacts actuated by said relays to set up successive circuits upon ionization of each'tube, a resistor in the cathode circuit of each of said thyratrons, and means for applying the voltage drop in said resistor to one control electrode of the successive tube to prepare each successive tube for operation, and means for applying impulses to be counted to the other control electrodes of all said thyratrons.

3. In a counting circuit, in combination, a plurality of thyratrons, each having a'cathode, an anode, and a pair of control electrodes, a relay in the space current circuit of each of said thyratrons, contacts actuated by said relays to set up successive circuits upon ionization of each tube, and to open the space current circuit of the previous tube, and means for applying a voltage drop in the space current circuit of each of said thyratrons to one control electrode of the successive tube to prepare each successive tube for operation, and means for applying impulses to be ssesseseess 5 a counted to the other control electrodes of all said thyratrons. 4. In a counting circuit, in combination, a plurality of thyratrons, each having a cathode, an 1 anode, and a pair d control electrodes, a relay in the space current circuit of each of said thyratrons, contacts actuated by said relays to set up successive circuits upon ionization of each tube, and to open the space current circuit of the previous tube, the last tube of the series opening its own space current path, and means for applying a voltage drop in the space current circuit of each of said thyratrons to one control electrode of the successive tube to prepare each successive tube for operation, and means for applying impulses to 'be counted to the other control electrodes of all said thyratrons.

5. In a counting circuit, in combination, a plurality of thyratrons, each having a cathode, an anode, and a pair of control electrodes, a relay in the space current circuit of each of said thyratrons, contacts actuated by said relays to set up successive circuits upon ionization of each tube, means for applying a voltage drop in the space current circuit of each of said thyratrons to one control electrode of the successive tube to prepare, 'each successive tube for operation, the corresponding control electrodes of each tube except the first having the same operating potential in the absence of'ionization of any tube, and means for applying impulses to be counted to the other control electrodes of all said thyratrons. 6. In a counting circuit, in combination, a plurality of thyratrons, each having a cathode, an anode, and. a pair of control electrodes, a relay in the space current circuit of each of said thyratrons, contacts actuated by said relays to set up successive circuits upon ionization of each tube, and means for applying a voltage drop in the space current circuit of each of said thyratrons to one control electrode of the successive tube to prepare each successive tube for operation, the potential difierence between corresponding control electrodes and the cathode of the various tubes except the first being either zero or a negative value, depending on whether the previous tube is ionized, and means for applying impulses to be counted to the other control electrodes of all said thyratrons.

7. In a counting circuit, in combination, a plurality of thyratrons. each having a cathode, an anode, and a pair of control electrodes, a relay in the space currentcircuit of each of said thyratrons, contacts actuated by said relays to set up successive circuits upon ionization of each tube,

I and means for applying a voltage drop in the space current circuit of each of said thyratrons to one control electrode of the successive tube to prepare each successive tube for operation, each of said tubes except the last including in its control circuit a voltage divider arranged so that the voltage at the midpoint thereof when a tube is ionized is the same as the voltage at the cathode of the following tube when said following tube is ionized, and means for applying impulses to be counted to the other control electrodes of all said thyratrons.

. 8. In a counting circuit, in combination, a plurality of thyratrons, each having a cathode, an anode, and a pair of control electrodes, a relay in the space current circuit of each of said thyratrons, contacts actuated by said relays to set up successive circuits upon ionization of each tube, means for applying a voltage drop in the space current circuit of each of said thyratrons to one 7 control electrode of the successive tube to prepare each successive tube for operation, and a condenser in shunt with a portion of said voltage di-' thyratrons.

ERNEST D. BURLINGAME. MADISON G. NICHOLSON, JR.

8 nmnncns crmn The following references are of record in the file oi this patent:

UNITED STATES PAIEN'I'S Number Name Date Burger et a1 Mar. 24, 1942 

